Description

These functions multiply their first argument
x
by
FLT_RADIX
(probably 2)
to the power of
exp,
that is:

x * FLT_RADIX ** exp

The definition of
FLT_RADIX
can be obtained by including
<float.h>.

Return Value

On success, these functions return
x
*
FLT_RADIX
**
exp.

If
x
or
exp
is a NaN, a NaN is returned.

If
x
is positive infinity (negative infinity),
and
exp
is not negative infinity,
positive infinity (negative infinity) is returned.

If
x
is +0 (-0), and
exp
is not positive infinity, +0 (-0) is returned.

If
x
is zero, and
exp
is positive infinity,
a domain error occurs, and
a NaN is returned.

If
x
is an infinity,
and
exp
is negative infinity,
a domain error occurs, and
a NaN is returned.

If the result overflows,
a range error occurs,
and the functions return
HUGE_VAL,
HUGE_VALF,
or
HUGE_VALL,
respectively, with a sign the same as
x.

If the result underflows,
a range error occurs,
and the functions return zero, with a sign the same as
x.

Errors

See
math_error(7)
for information on how to determine whether an error has occurred
when calling these functions.

The following errors can occur:

Domain error: x is 0, and exp is positive infinity, or x is positive infinity and exp is negative infinity and the other argument is not a NaN

An invalid floating-point exception
(FE_INVALID)
is raised.

Range error, overflow

An overflow floating-point exception
(FE_OVERFLOW)
is raised.

Range error, underflow

An underflow floating-point exception
(FE_UNDERFLOW)
is raised.

These functions do not set
errno.

Conforming To

scalb()
is specified in POSIX.1-2001, but marked obsolescent.
POSIX.1-2008 removes the specification of
scalb(),
recommending the use of
scalbln(3),
scalblnf(3),
or
scalblnl(3)
instead.
The
scalb()
function is from 4.3BSD.

scalbf()
and
scalbl()
are unstandardized;
scalbf()
is nevertheless present on several other systems

See Also

Colophon

This page is part of release 3.80 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
http://www.kernel.org/doc/man-pages/.

License & Copyright

Copyright 2004 Andries Brouwer .
and Copyright 2008, Linux Foundation, written by Michael Kerrisk
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